The current process is a bit tedious if you want to correctly replace several assets in entries. Currently, you have to reference each filename in your entry, then search for your file in assets, check that asset, use the dropdown to replace asset, and finally... replace asset.

Better method:

1. Double click asset (on entry)
2. Click edit (takes you to focal point/crop area)
3. Show replace asset option (allow for upload of new asset)